Mantis Shrimp

Malapascua Island, Philippines

The strangest underwater critter I have seen. Reminds me of an alien. I had to keep my distance from this Mantis Shrimp as his lightning fast claws can snap out and crack the dome port on a video housing. It’s been proven. The eye of a Mantis Shrimp is the most complex eyeball of any creature on earth. They figure they can see colours we can’t even imagine. Keep an eye on the eye and watch the pupil (or whatever it is) move up and down it’s oblong shape eye. Compared to the three types of colour-receptive cones that humans possess in their eyes, the eyes of a mantis shrimp carry 16 types of colour-receptive cones. Furthermore, some of these shrimp can tune the sensitivity of their long-wavelength vision to adapt to their environment.

Varieties range from shades of brown to vivid colors, as there are more than 450 species of mantis shrimp. They are among the most important predators in many shallow, tropical, and sub tropical marine habitats. However, despite being common, they are poorly understood as many species spend most of their life tucked away in burrows and holes.

Each compound eye is made up of up to ten thousand side-by-side ommatidia. Each eye consists of two flattened hemispheres separated by six parallel rows of specialised ommatidia, collectively called the midband. This divides the eye into three regions. What advantage sensitivity to polarization confers is unclear; however, polarization vision is used by other animals for sexual signaling and secret communication that avoids the attention of predators.

It has been suggested that the capacity to see UV light enables observation of otherwise hard-to-detect prey on coral reefs.

Many thanks to Wilbert Arriesgado our dive guide for the week at Thresher Shark Divers for his expert advice and keen eye. http://www.malapascua-diving.com/